Excavators



A. J. KELLY EXCAVATORS A R-n n, 1967 2 Sheets-Sheet 2 Filed Aug. 17, 1965 M w on 2% $5 w i mH K m. A

United States Patent 3,313,431 EXCAVATORS Alec J. Kelly, Stramshall, near Uttoxeter, England, assignor to J. C. Bamford (Excavators) Limited, Lakeside, Rocester, England, a British company Filed Aug. 17, 1965, Ser. No. 480,425 Claims priority, application Great Britain, Aug. 19, 1964, 33,828/64 16 Claims. (Cl. 214-138) This invention relates to excavators of the type which are generally operated from a tractor or other vehicle and which comprise a main boom, which at its lower end is pivotally connected to a king post assembly for movement up and down in a vertical plane, the boom having pivotally connected at its outer end, a dipper arm which carries or is adapted to carry a bucket or like tool and which is also, or arranged to be, pivoted for movement in a vertical plane.

In this type of excavator, the king post assembly is also capable of pivotal movement about a vertical axis so that the main boom can be rotated or slewed from one side to the other of the centre line of the tractor or other vehicle for the purpose of working to one side or the other side of the vehicle, and also there is a known construction in which the king post assembly is mounted upon a frame extending transversely of the centre line of the tractor or like vehicle, the king post assembly being slidable or adjustable along this frame so that it can be positioned at one extreme side of the frame for the purpose of working in a direction parallel to the centre line of the vehicle, such as when digging a trench or excavating, or clearing a ditch, where it is not possible to work along the centre line of the tractor.

This capability of being able to arrange the boom so that excavation can take place in a line parallel to, and offset from, the centre line of the vehicle, is advantageous in certain types of work, for example when excavating alongside an obstruction such as an existing wall which prevents the tractor from being positioned so as to enable the boom to' operate on the centre line. However, the extent to which the boom can be positioned for this type of operation, is limited by the side to side width of the transverse frame as the king post assembly can only be moved to the extreme end of the frame to obtain the maximum off-set and the width of the frame is limited to a size substantially of the same order as the overall width of the vehicle because of the requirements for travelling on public roads and also to ensure manoeuvreability of the tractor or other vehicle so that it can pass through normal size gateways and openings.

The main object of the present invention is to provide improvements in this type of excavator whereby the maximum amount of off-set from the centre line of the tractor for the working position of the main boom, may be substantially increased to enable the dipper arm to excavate on a line parallel to the centre line of the vehicle but at considerably greater distance therefrom than is possible 'with existing constructions.

A further object of the invention is to provide an improved form of excavator in which the direction of working of the bucket or like tool can be altered through any desired angle by manipulation of the boom and dipper arm without any substantial alteration in the position of the tractor. With existing arrangements, a change in the direction of working of the dipper arm Patented Apr. 11, 1967 'ice can only be brought about by manoeuvring the tractor so as to turn its centre line into alignment with, or parallel to, the new direction of Working.

With these objects in view, according to the invention we provide an excavator of the type specified, wherein the king post assembly is rotatable about a vertical axis so that the main boom which is connected to the king post assembly can be rotated therewith about the said vertical axis and wherein the dipper arm is mounted on the main boom so as to be rotatable relative to the boom about a further vertical axis in all operative positions of the boom as well as being rotatable about a horizontal axis to perform its normal excavating operations.

It will be appreciated that the vertical axis of rotation of the dipper arm must remain a vertical axis at all times and in all operative positions of the main boom and thus it will be appreciated that there must he means for adjusting the position of this vertical axis in relation to the main boom as the main bom moves up or down. If the aforesaid vertical axis were fixed in relation to the main boom when the boom was in a horizontal position for example, then when the boom was raised through an acute angle, the vertical axis would be tilted through the same angle and then any rotation of the dipper arm to one side or the other of the vertical plane containing the main boom, would result in tilting of the dipper arm and thus a sideways tilting of the bucket so that a trench having vertical sides could not then be excavated.

Conveniently, the aforesaid vertical axis for the dipper arm is provided in a link which is connected at one end to the main boom for pivotal movement about a horizontal axis and means are provided so that the angular position of this link relative to the main boom, is adjusted so as to always maintain the vertical axis as a true vertical axis irrespective of the angular position of the main boom relative to the horizontal.

According to a further feature of the invention, the aforesaid link having the vertical axis of rotation of the dipper arm mounted therein, is pivotally connected to the main boom about a horizontal axis and is further pivotally connected by means of a controlling link to a point on the king post assembly spaced from the pivotal connection between the king post and the main boom so as to form a parallel link assembly consisting of the main boom, the link having the vertical axis therein, the control link, and the portion of the king post assembly in between the pivotal connections of the main boom and control link.

With this arrangement of a parallel link assembly, the link carrying the vertical axis of rotation of the dipper arm will always be maintained at the correct angular relationship with the main boom to ensure the vertical axis remaining vertical at all times.

It will be seen therefore that with this arrangement, the king post assembly can be positioned at the extreme side of the transverse frame and then the boom can be swung so that it is at a position of to the cent-re line of the tractor and in this position the dipper arm can be rotated about its vertical axis until it extends in a direction parallel to the axis of the tractor and can then be operated in the normal way to excavate a trench parallel to the axis of the tractor and at a distance therefrom which is substantially greater than half the width of the transverse frame by the extra amount of offset given by the boom itself extending at right angles to the centre line of the tractor.

One embodiment of an excavator constructed according to the present invention will now be described in detail with reference to the accompanying drawings, wherein:

FIGURE 1 is a side elevation of an excavator constructed according to the present invention, and applied to a tractor.

FIGURE 2. is an end elevation of the excavator of FIG- URE 1, and,

FIGURE 3 is a plan view of the excavator of FIGURE 1 showing in chain dotted lines an alternative position of the main boom and dipper arm.

It will be apparent to those skilled in the art that there are various arrangements for the mounting of the dipper arm which may be adapted within the scope of the invention and therefore the following detailed description is given by way of example only in order to illustrate a practical embodiment of the invention.

The king post assembly 9 which supports the main boom 15 includes a king post 10 which is generally in the form of a vertical pivot pin capable of being rotated about a vertical axis and generally operated by hydraulic means indicated at 11, hydraulic rams 12, 13 and 14 are provided for lifting and lowering the main boom 15 and for the crowding of the dipper arm 16 and bucket 17 respectively.

Such king post assembly 9 is mounted upon a transverse frame 18 which may be secured to the rear of the tractor 21 so as to extend at right angles to the longitudinal centre line, which runs fore and aft of the tractor, and hydraulic means, not shown, are also provided for moving the king post assembly 9 to one side or the other of the centre line of the tractor 21 along the length of the transverse frame 18 and means, not shown, are also provided for clamping the king post assembly 9 in any desired position along the length of the frame 18. Such means are disclosed in US. Patent No. 3,156,488.

The main boom 15 is pivotally connected at its inner end 22 to a position 29 near the lower end 23 of the king post 10 and is raised and lowered by the hydraulic ram 12 pivotally connected between the upper end of the king post assembly 9 i.e. at 24, and a suitable position 25 adjacent the outer end 26 of the main boom 15.

At or near its outer end 26, the main boom 15 has connected thereto, a supporting link 27 which is pivotally connected about a horizontal axis to the main boom 15 at 28 and extends outwardly in a direction away from the tractor 21.

The dipper arm 16 which is of generally known form, carries an excavating or like bucket 17 at its operative end and the normal hydraulic ram 14 for operating this bucket 17 is provided on the upper side of the dipper arm 16 and the dipper arm 16 itself is pivotally connected, at 30, intermediate its ends to the forwardly projecting end of a bracket 29 which is itself mounted upon the supporting link 27 at 31 for pivotal movement about a vertical axis 35. The said bracket 29 has an extension 32 rearwardly in the direction towards the tractor 21 and the hydraulic ram 13 for operating the dipper arm 16 is connected pivotally at 33 to the end of this extension and also pivotally connected, at 36, to the other end of the dipper arm 16 remote from the bucket 17.

To maintain the support link 27 in the correct angular relationship with the main boom 15 to ensure that the vertical axis of rotation 35 of the dipper arm 16 is always vertical, there is provided a control link 37 which is disposed below the main boom 15 and is pivotally connected at 38 adjacent its outer end 39 to the aforesaid support link 27 and pivotally connected at 40 adjacent its inner end 41 to a point on the king post assembly 9 vertically below the pivotal connection 20 between the main boom 15 and the king post 10. The pivotal connection 38 between this control link 37 and the support link 27 is likewise vertically below the pivotal connection 28 between the support link 27 and the main boom 15 so that there is provided a parallel link arrangement consisting of the main boom 15 and control link 37 as the two longer opposed links and the support link 27 as the third link whilst the fourth link is the portion of the king post assembly between the pivotal connectisn 40 and 20 of the control link 37 and the main boom 15 respectively to the king post assembly 9.

With this arrangement therefore, in any angular position of the main boom 15 relative to the horizontal, the parallel link arrangement ensures that the support link 27 is in the correct angular relationship to maintain the true vertical axis of rotation 31 of the bracket 29 carrying the dipper arm 16.

The rotation of this bracket 29 about its vertical axis 31 may be achieved in any desired manner and conveniently with the use of one or more hydraulic rams arranged to operate a rack and pinion.

This is illustrated in the drawings and comprises a rack 42, housed within a housing 43, which extends trans versely of the link member 27. The rack 42 is operated by hydraulic rams, not shown, also within the housing 43, and on transverse movement of the rack 42, the pinion 44, with which the teeth of the rack are in mesh is caused to rotate, thereby pivoting the bracket 29 about the vertical axis of pivot 31. The pinion 44 takes the form of an approximately 270 quadrant.

Other methods (which are not shown in the drawings) may be used in rotating the bracket member about its vertical axis, for example, there may be one ram disposed to one side of the aforesaid bracket 29 and pivotally connected between such bracket 29 at one end and the support link 27 at the other end so that it can be operated by extending or retracting its piston rod to cause rotation of the bracket 29 carrying the dipper arm 16 in the appropriate direction. When only one ram is used, this may be moved from one side of the bracket 29 to the other when the operator decides to change the position of working of the dipper arm 16 from one side of the boom to the other. Alternatively, two rams operating on either side of the bracket member 29 may be used and instead of connecting the rams between the bracket member 29 and the support link 27, such rams may be connected between the bracket member 29 and the main boom 15.

With the above described arrangement, the maximum offset for the working position of the dipper arm 16 can be obtained to one side or the other of the tractor 21 when the king post assembly 9 is adjusted at the extreme end of the transverse frame 18 of the tractor and the main boom 15 is swung outwardly of the tractor 21 on this side until it is at right angles to the center line of the tractor. In this position the bracket 29 carrying the dipper arm 16 is rotated about its vertical axis 35 so as to bring the dipper arm 16 into a position at right angles to the main boom 15 and thus able to operate to excavate a trench which is parallel to the center line of the tractor 21 and spaced therefrom by half the width of the transverse frame 18 and the further substantial distance provided by the extent sideways of the main 'boom 15.

It will be appreciated that by rotation of the main boom 15 to an angle of less than to the center line of the tractor 21, as shown in chain-dotted lines in FIGURE 3, or movement of the king post assembly 9 inwards towards the center line of the tractor 21, or by a combination of these two movements, the dipper arm 16 can excavate a trench parallel to the center line of the tractor 21 at any position in between the maximum ofiset position and the center line or at an angle to the center line of the tractor 21.

Also when a change of direction is required such as a change through 90 when excavating footings for buildings, the arrangement of the present invention enables this change of direction to be made by appropriate manipulation of the main boom 15. If the dipper arm 16 is excavating at the maximum offset, then when the change of direction is required, the main boom 15 is swung so as to lie parallel to the center line of the tractor 21 and the dipper arm 16 is swung so as to extend at right angles to the main boom 15 and can then be operated to continue the excavation at right angles to the original direction with the main boom 15 being moved from one side to the other of the transverse frame 18.

What I claim then is:

1. An excavator for mounting on a vehicle, including, a rotatable king post assembly, attachment means adapted to be secured to a vehicle and on which attachment means the king post assembly is rotatably mounted about a vertical axis, means for rotating the king post assembly about said vertical axis, a main boom pivotally mounted upon the king post assembly about a horizontal axis for movement of the main boom up and down in a vertical plane, a dipper arm mounting assembly connected to the outer end of the main boom, a dipper arm pivotally mounted upon said mounting assembly about a horizontal axis for movement of the dipper arm up and down in a vertical plane and also pivotally mounted about a vertical axis upon said mounting assembly for movement of the dipper arm relative to the main boom about said vertical axis, link means connected between said dipper arm mounting assembly and the king post assembly for maintaining vertical said vertical axis of pivoting of the dipper arm in all operative positions of the main boom, a tool pivotally mounted upon the dipper arm about a horizontal axis for movement in a vertical plane, lifting and lowering means whereby the main boom is moved up and down in a vertical plane, crowding means for pivoting the dipper arm about its horizontal axis for up and down movement thereof in a vertical plane, traversing means for pivoting the dipper arm about its vertical axis and further crowding means adapted to rock the tool about the said horizontal axis for movement in a vertical plane.

2. An excavator for mounting on a vehicle, including a rotatable king post assembly, attachment means adapted to be secured to a vehicle and on which attachment means the king post assembly is rotatably mounted about a vertical axis, means for rotating the king post assembly about said vertical axis, a main boom pivotally mounted upon the king post assembly about a horizontal axis for movement of the main boom up and down in a vertical plane, a dipper arm mounting assembly connected to the outer end of the main boom, a dipper arm pivotally mounted upon said mounting assembly about a horizontal axis for movement of the dipper arm up and down in a vertical plane and also pivotally mounted about a vertical axis upon said mounting assembly for movement of the dipper arm relative to the main boom about said vertical axis in all operative positions of the main boom, said mounting assembly including a link member wherein the vertical axis of pivoting of the dipper arm is provided, pivot means whereby the link member is pivotally connected to the main boom about a horizontal axis, a controlling link pivotally connected at one end to the link member about a horizontal axis and pivotally connected at the other end to the king post assembly at a point spaced from the pivotal connection between the king post assembly and the main boom, so as to form a parallel link assembly consisting of the main boom, the link member having the vertical axis therein, the control link, and the part of the king post assembly between the pivotal connections of the main boom and control link.

3. An excavator according to claim 2, wherein poweroperated means are provided for rotating the dipper arm about a vertical axis.

4. An excavator according to claim 3, wherein the power-operated means comprises a rack bar mounted upon the link member with its longitudinal axis horizontal, means whereby the rack bar is moved to and fro in the direction of its longitudinal axis, a pinion secured to the dipper arm and meshing with the teeth of the rack bar so that when the rack bar is moved to and fro the pinion and the dipper arm are rotated about the vertical axis.

5. An excavator according to claim 4, wherein means for moving the rack bar to and fro comprises at least one hydraulic piston and cylinder unit.

6. An excavator according to claim 2, wherein the dipper arm is pivotally mounted for movement in a ver tical plane upon a bracket member and the bracket mem ber is pivotally mounted upon the link member about said vertical axis.

7. An excavator according to claim 5, wherein the dipper arm is pivotally mounted for movement in a vertical plane upon a bracket member and the bracket member is pivotally mounted upon the link member about said vertical axis.

8. An excavator according to claim 6, wherein the bracket member is provided with an extension part which extends rearwardly towards the vehicle and wherein an hydraulic ram for raising and lowering the dipper arm is pivotally connected between the rear end of the extension part and the end of the dipper arm distant from the end thereof arranged to carry the tool.

9. An excavator according to claim 7, wherein the bracket member is provided with an extension part which extends rearwardly towards the vehicle and wherein an hydraulic ram for raising and lowering the dipper arm is pivotally connected between the rear end of the extension part and the end of the dipper arm distant from the end thereof arranged to carry the tool.

10. An excavator according to claim 9, wherein the main boom, dipper arm, and tool are caused to move in a vertical plane about their respective pivotal connections by means of hydraulic piston and cylinder units.

11. An excavator according to claim 2, wherein the king post assembly is mounted so as to be movable horizontally relative to the vehicle.

12. An excavator according to claim 10, wherein the king post assembly is mounted so as to be movable horizontally relative to the vehicle.

13. An excavator according to claim 11, wherein the king post assembly is mounted on a frame capable of being secured to a vehicle and along which frame the king post assembly can be adjusted and can be clamped in any required position.

14. An excavator according to claim 12, wherein the king post assembly is mounted on a frame capable of being secured to a vehicle and along which frame the king post assembly can be adjusted and can be clamped in any required position.

15. An excavator for mounting on a vehicle including a rotatable king post assembly, attachment means adapted to be secured to a vehicle and on which means the king post assembly is rotatably mounted about a vertical axis, means for rotating the king post assembly about the said vertical axis, a main boom pivotally mounted upon the king post assembly about a horizontal axis for movement of the main boom up and down in a vertical plane, a control link pivotally mounted upon the king post assembly about a horizontal axis vertically below said pivotal connection between the king post assembly and the main boom, an hydraulic ram assembly pivotally connected between the king post assembly and the outer end of the main boom for movement of the main boom up and down, a link member pivotally connected about a horizontal axis to the outer end of the main boom, pivotal connecting means between the outer end of the control link and the portion of the link member vertically below said pivotal connection between the link member and the outer end of the main boom, a bracket member pivotally connected to the link assembly about a vertical axis, which axis is kept vertical by a parallel link assembly provided by the main boom, the link member having the vertical axis therein, the control link, and the part of the king post assembly between the pivotal connections of the main boom and control link, said bracket member having an extension part which extends rearwardly towards the vehicle, a dipper arm pivotally connected to the bracket member about a horizontal axis for movement of the dipper arm up and down a vertical plane, the dipper arm being adapted to carry at its outer end a tool pivotally mounted thereon about a horizontal axis for movement in a vertical plane, an hydraulic ram assembly pivotally connected between the extension part of the bracket member and the end of the dipper arm distant from the end which is adapted to carry the tool, and an hydraulic ram assembly arranged to be connected between the tool and the dipper arm for movement of the tool about a horizontal axis.

16. An excavator according to claim 15, wherein the king post assembly is mounted on a frame capable of being secured to a vehicle and along which frame the king post assembly can be adjusted and can be clamped in any required position.

References Cited by the Examiner 1O HUGO O. SCHULZ, Primary Examiner. 

1. AN EXCAVATOR FOR MOUNTING ON A VEHICLE, INCLUDING, A ROTATABLE KING POST ASSEMBLY, ATTACHMENT MEANS ADAPTED TO BE SECURED TO A VEHICLE AND ON WHICH ATTACHMENT MEANS THE KING POST ASSEMBLY IS ROTATABLY MOUNTED ABOUT A VERTICAL AXIS, MEANS FOR ROTATING THE KING POST ASSEMBLY ABOUT SAID VERTICAL AXIS, A MAIN BOOM PIVOTALLY MOUNTED UPON THE KING POST ASSEMBLY ABOUT A HORIZONTAL AXIS FOR MOVEMENT OF THE MAIN BOOM UP AND DOWN IN A VERTICAL PLANE, A DIPPER ARM MOUNTING ASSEMBLY CONNECTED TO THE OUTER END OF THE MAIN BOOM, A DIPPER ARM PIVOTALLY MOUNTED UPON SAID MOUNTING ASSEMBLY ABOUT A HORIZONTAL AXIS FOR MOVEMENT OF THE DIPPER ARM UP AND DOWN IN A VERTICAL PLANE AND ALSO PIVOTALLY MOUNTED ABOUT A VERTICAL AXIS UPON SAID MOUNTING ASSEMBLY FOR MOVEMENT OF THE DIPPER ARM RELATIVE TO THE MAIN BOOM ABOUT SAID VERTICAL AXIS, LINK MEANS CONNECTED BETWEEN SAID DIPPER ARM MOUNTING ASSEMBLY AND THE KING POST ASSEMBLY FOR MOUNTING VERTICAL SAID VERTICAL AXIS OF PIVOTING OF THE DIPPER ARM IN ALL OPERATIVE POSITIONS OF THE MAIN BOOM, A TOOL PIVOTALLY MOUNTED UPON THE DIPPER ARM ABOUT A HORIZONTAL AXIS FOR MOVEMENT IN A VERTICAL PLANE, LIFTING AND LOWERING MEANS WHEREBY THE MAIN BOOM IS MOVED UP AND DOWN IN A VERTICAL PLANE, CROWING MEANS FOR PIVOTING THE DIPPER ARM ABOUT ITS HORIZONTAL AXIS FOR UP AND DOWN MOVEMENT THEREOF IN A VERTICAL PLANE, TRAVERSING MEANS FOR PIVOTING THE DIPPER ARM ABOUT ITS VERTICAL AXIS AND FURTHER CROWDING MEANS ADAPTED TO ROCK THE TOOL ABOUT THE SAID HORIZONTAL AXIS FOR MOVEMENT IN A VERTICAL PLANE. 